New hydrogen instruction to reduce cost of growing an array on keyed stores.

src/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5312 matching lines @@
   DCHECK(ToRegister(instr->key()).is(StoreDescriptor::NameRegister()));
   DCHECK(ToRegister(instr->value()).is(StoreDescriptor::ValueRegister()));
 
   Handle<Code> ic = CodeFactory::KeyedStoreICInOptimizedCode(
                         isolate(), instr->language_mode(),
                         instr->hydrogen()->initialization_state()).code();
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
 }
 
 
+void LCodeGen::DoMaybeGrowElements(LMaybeGrowElements* instr) {
+  class DeferredMaybeGrowElements final : public LDeferredCode {
+   public:
+    DeferredMaybeGrowElements(LCodeGen* codegen, LMaybeGrowElements* instr)
+        : LDeferredCode(codegen), instr_(instr) {}
+    void Generate() override { codegen()->DoDeferredMaybeGrowElements(instr_); }
+    LInstruction* instr() override { return instr_; }
+
+   private:
+    LMaybeGrowElements* instr_;
+  };
+
+  Register result = x0;
+  DeferredMaybeGrowElements* deferred =
+      new (zone()) DeferredMaybeGrowElements(this, instr);
+  LOperand* key = instr->key();
+  LOperand* current_capacity = instr->current_capacity();
+
+  DCHECK(instr->hydrogen()->key()->representation().IsInteger32());
+  DCHECK(instr->hydrogen()->current_capacity()->representation().IsInteger32());
+  DCHECK(key->IsConstantOperand() || key->IsRegister());
+  DCHECK(current_capacity->IsConstantOperand() ||
+         current_capacity->IsRegister());
+
+  if (key->IsConstantOperand() && current_capacity->IsConstantOperand()) {
+    int32_t constant_key = ToInteger32(LConstantOperand::cast(key));
+    int32_t constant_capacity =
+        ToInteger32(LConstantOperand::cast(current_capacity));
+    if (constant_key >= constant_capacity) {
+      // Deferred case.
+      __ B(deferred->entry());
+    }
+  } else if (key->IsConstantOperand()) {
+    int32_t constant_key = ToInteger32(LConstantOperand::cast(key));
+    __ Cmp(ToRegister(current_capacity), Operand(constant_key));
+    __ B(le, deferred->entry());
+  } else if (current_capacity->IsConstantOperand()) {
+    int32_t constant_capacity =
+        ToInteger32(LConstantOperand::cast(current_capacity));
+    __ Cmp(ToRegister(key), Operand(constant_capacity));
+    __ B(ge, deferred->entry());
+  } else {
+    __ Cmp(ToRegister(key), ToRegister(current_capacity));
+    __ B(ge, deferred->entry());
+  }
+
+  __ Mov(result, ToRegister(instr->elements()));
+
+  __ Bind(deferred->exit());
+}
+
+
+void LCodeGen::DoDeferredMaybeGrowElements(LMaybeGrowElements* instr) {
+  // TODO(3095996): Get rid of this. For now, we need to make the
+  // result register contain a valid pointer because it is already
+  // contained in the register pointer map.
+  Register result = x0;
+  __ Mov(result, 0);
+
+  // We have to call a stub.
+  {
+    PushSafepointRegistersScope scope(this);
+    __ Move(result, ToRegister(instr->object()));
+
+    LOperand* key = instr->key();
+    if (key->IsConstantOperand()) {
+      __ Mov(x3, Operand(ToSmi(LConstantOperand::cast(key))));
+    } else {
+      __ Mov(x3, ToRegister(key));
+      __ SmiTag(x3);
+    }
+
+    GrowArrayElementsStub stub(isolate(), instr->hydrogen()->is_js_array(),
+                               instr->hydrogen()->kind());
+    __ CallStub(&stub);
+    RecordSafepointWithLazyDeopt(
+        instr, RECORD_SAFEPOINT_WITH_REGISTERS_AND_NO_ARGUMENTS);
+    __ StoreToSafepointRegisterSlot(result, result);
+  }
+
+  // Deopt on smi, which means the elements array changed to dictionary mode.
+  DeoptimizeIfSmi(result, instr, Deoptimizer::kSmi);
+}
+
+
 void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   Representation representation = instr->representation();
 
   Register object = ToRegister(instr->object());
   HObjectAccess access = instr->hydrogen()->access();
   int offset = access.offset();
 
   if (access.IsExternalMemory()) {
     DCHECK(!instr->hydrogen()->has_transition());
     DCHECK(!instr->hydrogen()->NeedsWriteBarrier());
@@ skipping 707 matching lines @@
   Handle<ScopeInfo> scope_info = instr->scope_info();
   __ Push(scope_info);
   __ Push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 
 } }  // namespace v8::internal